First of all, at recess we were made to go outside and do physical things. Usually without any supervision. We burned the calories we ate.
And I'll wager dollars to donuts that you played on jungle gyms, wrestled and tussled, pointed fingers and yelled "bang, bang, you're dead!", threw dodge balls at each other, played Red Rover, Red Rover, and chased each other around. It's a miracle you're alive today, VSA. Truly a miracle.